Many different types of evaluations are carried out on meat products before they are approved for commercial sale. Some of these procedures involve a system of grading depending upon fat and muscle content and distribution, while others involve condemnation decisions.
Various types of ultrasonic apparatus for examining the internal structure of humans and animals are, of course, well known in the prior art. The use of ultrasonic techniques for inspecting live animals for fat thickness has long been proposed, particularly in percentage of fat, so that the fat indication provides a reasonable indication of carcass composition.
The advantage of using ultrasonic apparatus to inspect and grade livestock are numerous. Primarily, an animal's value can be assessed prior to death, which can be very important for herd evaluation and selection of breeding stock. After the initial investment in the equipment, the process of livestock evaluation, is quick and inexpensive and in no way harms the animal because the ultrasonic waves are not damaging and do not require expensive film developing procedures as with X-ray.
A grading determination is based upon the relative quantity of fat or muscle within a normal set of parameters. The normal set of parameters are the same for each animal within a particular species (e.g. the number of fat or muscle layers) whereas the proportion each type of tissue within these parameters differs for each individual animal. Ultrasound techniques have been used extensively to determine grading characteristics of livestock.
A condemnation or sorting decision involves comparing each animal against a norm reference for its particular species and condemning (--eliminating from the food supply) any animals showing any abnormal conditions indicative of disease or other health related problems. Quantity of the abnormality is generally not a factor, but rather its presence or absence is enough. Heretofore, ultrasound technology has not been used in the condemnation sorting decision made by meat inspectors.
Many abnormalities that require condemnation affect the skeletal structure of animals. While ultrasonic apparatus and methods have been used extensively to evaluate and characterize tissue and conditions causing tissue damage, ultrasound technology has not been used to characterize or evaluate bone structure. Ultrasonic waves do not pass through bone, therefore the only image presented is an outline of the bone rather than a cross-sectional image as is shown of other tissues (e.g. muscle and fat layers).
Many post mortem inspection processes involve first inspecting a whole carcass to look for suspected problems, and actually cutting into a suspected infected animal to further evaluate the amount of damage. Often the animal turns out to be healthy, but has still been significantly reduced in value because of the disruption of an otherwise whole animal part. One such inspection that is carried out, is an inspection for osteomyelitis. Osteomyelitis is a bone disorder in poultry resulting from Staphylococcal auerus infection which is the primary cause of food poisoning in humans eating poultry. Osteomyelitis is discussed in "Studies on the pathogenesis of staphylococcal osteomyelitis in chickens,--I. Effect of Stress on Experimentally Induced Osteomyelitis", by Mutalib et al--Avian Dis., Vol. 27, No. 1, January-March 1983 pg 141-156, incorporated herein by reference.
Long bones, e.g. tibia, which are infected by Staphylococcal auerus become inflamed and enlarged (osteomyelitis) and the Staph. auerus may be transmissible to humans. Currently Federal Meat Inspectors cut soft tissue and bones of possibly inflamed tibia at the femur joints to observe the marrow. On average only 10% of the cut carcasses are diseased, which means the industry is losing enormous amounts of money on the 90% of otherwise healthy poultry by using this method of inspection.
Using X-ray equipment to analyze conditions affecting the bone structure of an animal is impractical and expensive. The industry is in need of an inspection technique for osteomyelitis that does not require the cutting of so many healthy poultry falsely suspected of infection.